sqliteInt.h revision c5c4113dfcabb1eed3d4bdf7609de5170027a794
#pragma ident "%Z%%M% %I% %E% SMI"
/*
** 2001 September 15
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.220.2.1 2004/07/15 13:37:05 drh Exp $
*/
#include "config.h"
#include "sqlite.h"
#include "hash.h"
#include "parse.h"
#include "btree.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
/*
** The maximum number of in-memory pages to use for the main database
** table and for temporary tables.
*/
#define MAX_PAGES 2000
#define TEMP_PAGES 500
/*
** If the following macro is set to 1, then NULL values are considered
** distinct for the SELECT DISTINCT statement and for UNION or EXCEPT
** compound queries. No other SQL database engine (among those tested)
** works this way except for OCELOT. But the SQL92 spec implies that
** this is how things should work.
**
** If the following macro is set to 0, then NULLs are indistinct for
** SELECT DISTINCT and for UNION.
*/
#define NULL_ALWAYS_DISTINCT 0
/*
** If the following macro is set to 1, then NULL values are considered
** distinct when determining whether or not two entries are the same
** in a UNIQUE index. This is the way PostgreSQL, Oracle, DB2, MySQL,
** OCELOT, and Firebird all work. The SQL92 spec explicitly says this
** is the way things are suppose to work.
**
** If the following macro is set to 0, the NULLs are indistinct for
** a UNIQUE index. In this mode, you can only have a single NULL entry
** for a column declared UNIQUE. This is the way Informix and SQL Server
** work.
*/
#define NULL_DISTINCT_FOR_UNIQUE 1
/*
** The maximum number of attached databases. This must be at least 2
** in order to support the main database file (0) and the file used to
** hold temporary tables (1). And it must be less than 256 because
** an unsigned character is used to stored the database index.
*/
#define MAX_ATTACHED 10
/*
** The next macro is used to determine where TEMP tables and indices
** are stored. Possible values:
**
** 0 Always use a temporary files
** 1 Use a file unless overridden by "PRAGMA temp_store"
** 2 Use memory unless overridden by "PRAGMA temp_store"
** 3 Always use memory
*/
#ifndef TEMP_STORE
# define TEMP_STORE 1
#endif
/*
** When building SQLite for embedded systems where memory is scarce,
** you can define one or more of the following macros to omit extra
** features of the library and thus keep the size of the library to
** a minimum.
*/
/* #define SQLITE_OMIT_AUTHORIZATION 1 */
/* #define SQLITE_OMIT_INMEMORYDB 1 */
/* #define SQLITE_OMIT_VACUUM 1 */
/* #define SQLITE_OMIT_DATETIME_FUNCS 1 */
/* #define SQLITE_OMIT_PROGRESS_CALLBACK 1 */
/*
** Integers of known sizes. These typedefs might change for architectures
** where the sizes very. Preprocessor macros are available so that the
** types can be conveniently redefined at compile-type. Like this:
**
** cc '-DUINTPTR_TYPE=long long int' ...
*/
#ifndef UINT32_TYPE
# define UINT32_TYPE unsigned int
#endif
#ifndef UINT16_TYPE
# define UINT16_TYPE unsigned short int
#endif
#ifndef INT16_TYPE
# define INT16_TYPE short int
#endif
#ifndef UINT8_TYPE
# define UINT8_TYPE unsigned char
#endif
#ifndef INT8_TYPE
# define INT8_TYPE signed char
#endif
#ifndef INTPTR_TYPE
# if SQLITE_PTR_SZ==4
# define INTPTR_TYPE int
# else
# define INTPTR_TYPE long long
# endif
#endif
/*
** Defer sourcing vdbe.h until after the "u8" typedef is defined.
*/
#include "vdbe.h"
/*
** Most C compilers these days recognize "long double", don't they?
** Just in case we encounter one that does not, we will create a macro
** for long double so that it can be easily changed to just "double".
*/
#ifndef LONGDOUBLE_TYPE
# define LONGDOUBLE_TYPE long double
#endif
/*
** This macro casts a pointer to an integer. Useful for doing
** pointer arithmetic.
*/
/*
** The maximum number of bytes of data that can be put into a single
** row of a single table. The upper bound on this limit is 16777215
** bytes (or 16MB-1). We have arbitrarily set the limit to just 1MB
** here because the overflow page chain is inefficient for really big
** records and we want to discourage people from thinking that
** multi-megabyte records are OK. If your needs are different, you can
** change this define and recompile to increase or decrease the record
** size.
**
** The 16777198 is computed as follows: 238 bytes of payload on the
** original pages plus 16448 overflow pages each holding 1020 bytes of
** data.
*/
#define MAX_BYTES_PER_ROW 1048576
/* #define MAX_BYTES_PER_ROW 16777198 */
/*
** If memory allocation problems are found, recompile with
**
** -DMEMORY_DEBUG=1
**
** to enable some sanity checking on malloc() and free(). To
** check for memory leaks, recompile with
**
** -DMEMORY_DEBUG=2
**
** and a line of text will be written to standard error for
** each malloc() and free(). This output can be analyzed
** by an AWK script to determine if there are any leaks.
*/
#ifdef MEMORY_DEBUG
void sqliteStrRealloc(char**);
#else
# define sqliteRealloc_(X,Y) sqliteRealloc(X,Y)
# define sqliteStrRealloc(X)
#endif
/*
** This variable gets set if malloc() ever fails. After it gets set,
** the SQLite library shuts down permanently.
*/
extern int sqlite_malloc_failed;
/*
** The following global variables are used for testing and debugging
** only. They only work if MEMORY_DEBUG is defined.
*/
#ifdef MEMORY_DEBUG
extern int sqlite_nMalloc; /* Number of sqliteMalloc() calls */
extern int sqlite_nFree; /* Number of sqliteFree() calls */
extern int sqlite_iMallocFail; /* Fail sqliteMalloc() after this many calls */
#endif
/*
** Name of the master database table. The master database table
** is a special table that holds the names and attributes of all
** user tables and indices.
*/
#define MASTER_NAME "sqlite_master"
#define TEMP_MASTER_NAME "sqlite_temp_master"
/*
** The name of the schema table.
*/
/*
** A convenience macro that returns the number of elements in
** an array.
*/
#define ArraySize(X) (sizeof(X)/sizeof(X[0]))
/*
** Forward references to structures
*/
typedef struct Instruction Instruction;
typedef struct WhereLevel WhereLevel;
typedef struct TriggerStep TriggerStep;
typedef struct TriggerStack TriggerStack;
typedef struct AuthContext AuthContext;
/*
** Each database file to be accessed by the system is an instance
** of the following structure. There are normally two of these structures
** in the sqlite.aDb[] array. aDb[0] is the main database file and
** aDb[1] is the database file used to hold temporary tables. Additional
** databases may be attached.
*/
struct Db {
char *zName; /* Name of this database */
int schema_cookie; /* Database schema version number for this file */
void *pAux; /* Auxiliary data. Usually NULL */
void (*xFreeAux)(void*); /* Routine to free pAux */
};
/*
** These macros can be used to test, set, or clear bits in the
** Db.flags field.
*/
/*
** Allowed values for the DB.flags field.
**
** The DB_Locked flag is set when the first OP_Transaction or OP_Checkpoint
** opcode is emitted for a database. This prevents multiple occurances
** of those opcodes for the same database in the same program. Similarly,
** the DB_Cookie flag is set when the OP_VerifyCookie opcode is emitted,
** and prevents duplicate OP_VerifyCookies from taking up space and slowing
** down execution.
**
** The DB_SchemaLoaded flag is set after the database schema has been
** read into internal hash tables.
**
** DB_UnresetViews means that one or more views have column names that
** have been filled out. If the schema changes, these column names might
** changes and so the view will need to be reset.
*/
/*
** Each database is an instance of the following structure.
**
** The sqlite.file_format is initialized by the database file
** and helps determines how the data in the database file is
** represented. This field allows newer versions of the library
** to read and write older databases. The various file formats
** are as follows:
**
** file_format==1 Version 2.1.0.
** file_format==2 Version 2.2.0. Add support for INTEGER PRIMARY KEY.
** file_format==3 Version 2.6.0. Fix empty-string index bug.
** file_format==4 Version 2.7.0. Add support for separate numeric and
** text datatypes.
**
** The sqlite.temp_store determines where temporary database files
** are stored. If 1, then a file is created to hold those tables. If
** 2, then they are held in memory. 0 means use the default value in
** the TEMP_STORE macro.
**
** The sqlite.lastRowid records the last insert rowid generated by an
** insert statement. Inserts on views do not affect its value. Each
** trigger has its own context, so that lastRowid can be updated inside
** triggers as usual. The previous value will be restored once the trigger
** exits. Upon entering a before or instead of trigger, lastRowid is no
** longer (since after version 2.8.12) reset to -1.
**
** The sqlite.nChange does not count changes within triggers and keeps no
** context. It is reset at start of sqlite_exec.
** The sqlite.lsChange represents the number of changes made by the last
** insert, update, or delete statement. It remains constant throughout the
** length of a statement and is then updated by OP_SetCounts. It keeps a
** context stack just like lastRowid so that the count of changes
** within a trigger is not seen outside the trigger. Changes to views do not
** affect the value of lsChange.
** The sqlite.csChange keeps track of the number of current changes (since
** the last statement) and is used to update sqlite_lsChange.
*/
struct sqlite {
int nDb; /* Number of backends currently in use */
int flags; /* Miscellanous flags. See below */
int next_cookie; /* Next value of aDb[0].schema_cookie */
int cache_size; /* Number of pages to use in the cache */
int nTable; /* Number of tables in the database */
void *pBusyArg; /* 1st Argument to the busy callback */
int (*xBusyCallback)(void *,const char*,int); /* The busy callback */
void *pCommitArg; /* Argument to xCommitCallback() */
int (*xCommitCallback)(void*);/* Invoked at every commit. */
int lastRowid; /* ROWID of most recent insert (see above) */
int priorNewRowid; /* Last randomly generated ROWID */
int magic; /* Magic number for detect library misuse */
int nChange; /* Number of rows changed (see above) */
int lsChange; /* Last statement change count (see above) */
int csChange; /* Current statement change count (see above) */
struct sqliteInitInfo { /* Information used during initialization */
int iDb; /* When back is being initialized */
int newTnum; /* Rootpage of table being initialized */
} init;
void (*xTrace)(void*,const char*); /* Trace function */
void *pTraceArg; /* Argument to the trace function */
#ifndef SQLITE_OMIT_AUTHORIZATION
int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);
/* Access authorization function */
void *pAuthArg; /* 1st argument to the access auth function */
#endif
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
int (*xProgress)(void *); /* The progress callback */
void *pProgressArg; /* Argument to the progress callback */
int nProgressOps; /* Number of opcodes for progress callback */
#endif
};
/*
** Possible values for the sqlite.flags and or Db.flags fields.
**
** On sqlite.flags, the SQLITE_InTrans value means that we have
** executed a BEGIN. On Db.flags, SQLITE_InTrans means a statement
** transaction is active on that particular database file.
*/
/* DELETE, or UPDATE and return */
/* the count using a callback. */
/* result set is empty */
/* in 4th argument of callback */
/*
** Possible values for the sqlite.magic field.
** The numbers are obtained at random and have no special meaning, other
** than being distinct from one another.
*/
/*
** Each SQL function is defined by an instance of the following
** structure. A pointer to this structure is stored in the sqlite.aFunc
** hash table. When multiple functions have the same name, the hash table
** points to a linked list of these structures.
*/
struct FuncDef {
signed char nArg; /* Number of arguments. -1 means unlimited */
signed char dataType; /* Arg that determines datatype. -1=NUMERIC, */
/* -2=TEXT. -3=SQLITE_ARGS */
void *pUserData; /* User data parameter */
};
/*
** information about each column of an SQL table is held in an instance
** of this structure.
*/
struct Column {
char *zName; /* Name of this column */
char *zDflt; /* Default value of this column */
char *zType; /* Data type for this column */
};
/*
** The allowed sort orders.
**
** The TEXT and NUM values use bits that do not overlap with DESC and ASC.
** That way the two can be combined into a single number.
*/
#define SQLITE_SO_UNK 0 /* Use the default collating type. (SCT_NUM) */
#define SQLITE_SO_ASC 0 /* Sort in ascending order */
/*
** Each SQL table is represented in memory by an instance of the
** following structure.
**
** Table.zName is the name of the table. The case of the original
** CREATE TABLE statement is stored, but case is not significant for
** comparisons.
**
** Table.nCol is the number of columns in this table. Table.aCol is a
** pointer to an array of Column structures, one for each column.
**
** If the table has an INTEGER PRIMARY KEY, then Table.iPKey is the index of
** the column that is that key. Otherwise Table.iPKey is negative. Note
** that the datatype of the PRIMARY KEY must be INTEGER for this field to
** be set. An INTEGER PRIMARY KEY is used as the rowid for each row of
** the table. If a table has no INTEGER PRIMARY KEY, then a random rowid
** is generated for each row of the table. Table.hasPrimKey is true if
** the table has any PRIMARY KEY, INTEGER or otherwise.
**
** Table.tnum is the page number for the root BTree page of the table in the
** database file. If Table.iDb is the index of the database table backend
** in sqlite.aDb[]. 0 is for the main database and 1 is for the file that
** holds temporary tables and indices. If Table.isTransient
** is true, then the table is stored in a file that is automatically deleted
** when the VDBE cursor to the table is closed. In this case Table.tnum
** refers VDBE cursor number that holds the table open, not to the root
** page number. Transient tables are used to hold the results of a
** sub-query that appears instead of a real table name in the FROM clause
** of a SELECT statement.
*/
struct Table {
char *zName; /* Name of the table */
int nCol; /* Number of columns in this table */
int iPKey; /* If not less then 0, use aCol[iPKey] as the primary key */
int tnum; /* Root BTree node for this table (see note above) */
};
/*
** Each foreign key constraint is an instance of the following structure.
**
** A foreign key is associated with two tables. The "from" table is
** the table that contains the REFERENCES clause that creates the foreign
** key. The "to" table is the table that is named in the REFERENCES clause.
** Consider this example:
**
** CREATE TABLE ex1(
** a INTEGER PRIMARY KEY,
** b INTEGER CONSTRAINT fk1 REFERENCES ex2(x)
** );
**
** For foreign key "fk1", the from-table is "ex1" and the to-table is "ex2".
**
** Each REFERENCES clause generates an instance of the following structure
** which is attached to the from-table. The to-table need not exist when
** the from-table is created. The existance of the to-table is not checked
** until an attempt is made to insert data into the from-table.
**
** The sqlite.aFKey hash table stores pointers to this structure
** given the name of a to-table. For each to-table, all foreign keys
** associated with that table are on a linked list using the FKey.pNextTo
** field.
*/
struct FKey {
char *zTo; /* Name of table that the key points to */
int nCol; /* Number of columns in this key */
struct sColMap { /* Mapping of columns in pFrom to columns in zTo */
int iFrom; /* Index of column in pFrom */
char *zCol; /* Name of column in zTo. If 0 use PRIMARY KEY */
} *aCol; /* One entry for each of nCol column s */
};
/*
** SQLite supports many different ways to resolve a contraint
** error. ROLLBACK processing means that a constraint violation
** causes the operation in process to fail and for the current transaction
** to be rolled back. ABORT processing means the operation in process
** fails and any prior changes from that one operation are backed out,
** but the transaction is not rolled back. FAIL processing means that
** the operation in progress stops and returns an error code. But prior
** changes due to the same operation are not backed out and no rollback
** occurs. IGNORE means that the particular row that caused the constraint
** error is not inserted or updated. Processing continues and no error
** is returned. REPLACE means that preexisting database rows that caused
** a UNIQUE constraint violation are removed so that the new insert or
** update can proceed. Processing continues and no error is reported.
**
** RESTRICT, SETNULL, and CASCADE actions apply only to foreign keys.
** RESTRICT is the same as ABORT for IMMEDIATE foreign keys and the
** same as ROLLBACK for DEFERRED keys. SETNULL means that the foreign
** key is set to NULL. CASCADE means that a DELETE or UPDATE of the
** referenced table row is propagated into the row that holds the
** foreign key.
**
** The following symbolic values are used to record which type
** of action to take.
*/
#define OE_None 0 /* There is no constraint to check */
/*
** Each SQL index is represented in memory by an
** instance of the following structure.
**
** The columns of the table that are to be indexed are described
** by the aiColumn[] field of this structure. For example, suppose
** we have the following table and index:
**
** CREATE TABLE Ex1(c1 int, c2 int, c3 text);
** CREATE INDEX Ex2 ON Ex1(c3,c1);
**
** In the Table structure describing Ex1, nCol==3 because there are
** three columns in the table. In the Index structure describing
** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.
** The value of aiColumn is {2, 0}. aiColumn[0]==2 because the
** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].
** The second column to be indexed (c1) has an index of 0 in
** Ex1.aCol[], hence Ex2.aiColumn[1]==0.
**
** The Index.onError field determines whether or not the indexed columns
** must be unique and what to do if they are not. When Index.onError=OE_None,
** it means this is not a unique index. Otherwise it is a unique index
** and the value of Index.onError indicate the which conflict resolution
** algorithm to employ whenever an attempt is made to insert a non-unique
** element.
*/
struct Index {
char *zName; /* Name of this index */
int nColumn; /* Number of columns in the table used by this index */
int *aiColumn; /* Which columns are used by this index. 1st is 0 */
int tnum; /* Page containing root of this index in database file */
};
/*
** Each token coming out of the lexer is an instance of
** this structure. Tokens are also used as part of an expression.
**
** Note if Token.z==0 then Token.dyn and Token.n are undefined and
** may contain random values. Do not make any assuptions about Token.dyn
** and Token.n when Token.z==0.
*/
struct Token {
const char *z; /* Text of the token. Not NULL-terminated! */
unsigned n : 31; /* Number of characters in this token */
};
/*
** Each node of an expression in the parse tree is an instance
** of this structure.
**
** Expr.op is the opcode. The integer parser token codes are reused
** as opcodes here. For example, the parser defines TK_GE to be an integer
** code representing the ">=" operator. This same integer code is reused
** to represent the greater-than-or-equal-to operator in the expression
** tree.
**
** of argument if the expression is a function.
**
** Expr.token is the operator token for this node. For some expressions
** that have subexpressions, Expr.token can be the complete text that gave
** rise to the Expr. In the latter case, the token is marked as being
** a compound token.
**
** An expression of the form ID or ID.ID refers to a column in a table.
** For such expressions, Expr.op is set to TK_COLUMN and Expr.iTable is
** the integer cursor number of a VDBE cursor pointing to that table and
** Expr.iColumn is the column number for the specific column. If the
** expression is used as a result in an aggregate SELECT, then the
** value is also stored in the Expr.iAgg column in the aggregate so that
** it can be accessed after all aggregates are computed.
**
** If the expression is a function, the Expr.iTable is an integer code
** representing which function. If the expression is an unbound variable
** marker (a question mark character '?' in the original SQL) then the
** Expr.iTable holds the index number for that variable.
**
** The Expr.pSelect field points to a SELECT statement. The SELECT might
** be the right operand of an IN operator. Or, if a scalar SELECT appears
** in an expression the opcode is TK_SELECT and Expr.pSelect is the only
** operand.
*/
struct Expr {
** or in "<expr> IN (<expr-list)" */
** iColumn-th field of the iTable-th table. */
int iAgg; /* When op==TK_COLUMN and pParse->useAgg==TRUE, pull
** result from the iAgg-th element of the aggregator */
** right side of "<expr> IN (<select>)" */
};
/*
** The following are the meanings of bits in the Expr.flags field.
*/
/*
** These macros can be used to test, set, or clear bits in the
** Expr.flags field.
*/
#define ExprHasProperty(E,P) (((E)->flags&(P))==(P))
#define ExprHasAnyProperty(E,P) (((E)->flags&(P))!=0)
#define ExprSetProperty(E,P) (E)->flags|=(P)
#define ExprClearProperty(E,P) (E)->flags&=~(P)
/*
** A list of expressions. Each expression may optionally have a
** as the list of "expr AS ID" fields following a "SELECT" or in the
** list of "ID = expr" items in an UPDATE. A list of expressions can
** also be used as the argument to a function, in which case the a.zName
** field is not used.
*/
struct ExprList {
int nExpr; /* Number of expressions on the list */
int nAlloc; /* Number of entries allocated below */
struct ExprList_item {
char *zName; /* Token associated with this expression */
} *a; /* One entry for each expression */
};
/*
** An instance of this structure can hold a simple list of identifiers,
** such as the list "a,b,c" in the following statements:
**
** INSERT INTO t(a,b,c) VALUES ...;
** CREATE INDEX idx ON t(a,b,c);
** CREATE TRIGGER trig BEFORE UPDATE ON t(a,b,c) ...;
**
** The IdList.a.idx field is used when the IdList represents the list of
** column names after a table name in an INSERT statement. In the statement
**
** INSERT INTO t(a,b,c) ...
**
** If "a" is the k-th column of table "t", then IdList.a[0].idx==k.
*/
struct IdList {
int nId; /* Number of identifiers on the list */
int nAlloc; /* Number of entries allocated for a[] below */
struct IdList_item {
char *zName; /* Name of the identifier */
int idx; /* Index in some Table.aCol[] of a column named zName */
} *a;
};
/*
** The following structure describes the FROM clause of a SELECT statement.
** Each table or subquery in the FROM clause is a separate element of
** the SrcList.a[] array.
**
** With the addition of multiple database support, the following structure
** can also be used to describe a particular table such as the table that
** is modified by an INSERT, DELETE, or UPDATE statement. In standard SQL,
** such a table must be a simple name: ID. But in SQLite, the table can
** now be identified by a database name, a dot, then the table name: ID.ID.
*/
struct SrcList {
struct SrcList_item {
char *zDatabase; /* Name of database holding this table */
char *zName; /* Name of the table */
char *zAlias; /* The "B" part of a "A AS B" phrase. zName is the "A" */
int jointype; /* Type of join between this table and the next */
int iCursor; /* The VDBE cursor number used to access this table */
} a[1]; /* One entry for each identifier on the list */
};
/*
** Permitted values of the SrcList.a.jointype field
*/
/*
** For each nested loop in a WHERE clause implementation, the WhereInfo
** structure contains a single instance of this structure. This structure
** is intended to be private the the where.c module and should not be
** access or modified by other modules.
*/
struct WhereLevel {
int iMem; /* Memory cell used by this level */
int iCur; /* Cursor number used for this index */
int score; /* How well this indexed scored */
int brk; /* Jump here to break out of the loop */
int cont; /* Jump here to continue with the next loop cycle */
int iLeftJoin; /* Memory cell used to implement LEFT OUTER JOIN */
int top; /* First instruction of interior of the loop */
int bRev; /* Do the scan in the reverse direction */
};
/*
** The WHERE clause processing routine has two halves. The
** first part does the start of the WHERE loop and the second
** half does the tail of the WHERE loop. An instance of
** this structure is returned by the first half and passed
** into the second half to give some continuity.
*/
struct WhereInfo {
int iContinue; /* Jump here to continue with next record */
int iBreak; /* Jump here to break out of the loop */
int nLevel; /* Number of nested loop */
int savedNTab; /* Value of pParse->nTab before WhereBegin() */
int peakNTab; /* Value of pParse->nTab after WhereBegin() */
};
/*
** An instance of the following structure contains all information
** needed to generate code for a single SELECT statement.
**
** The zSelect field is used when the Select structure must be persistent.
** Normally, the expression tree points to tokens in the original input
** string that encodes the select. But if the Select structure must live
** longer than its input string (for example when it is used to describe
** a VIEW) we have to make a copy of the input string so that the nodes
** of the expression tree will have something to point to. zSelect is used
** to hold that copy.
**
** nLimit is set to -1 if there is no LIMIT clause. nOffset is set to 0.
** If there is a LIMIT clause, the parser sets nLimit to the value of the
** limit and nOffset to the value of the offset (or 0 if there is not
** offset). But later on, nLimit and nOffset become the memory locations
** in the VDBE that record the limit and offset counters.
*/
struct Select {
char *zSelect; /* Complete text of the SELECT command */
};
/*
** The results of a select can be distributed in several ways.
*/
/*
** When a SELECT uses aggregate functions (like "count(*)" or "avg(f1)")
** we have to do some additional analysis of expressions. An instance
** of the following structure holds information about a single subexpression
** somewhere in the SELECT statement. An array of these structures holds
** all the information we need to generate code for aggregate
** expressions.
**
** Note that when analyzing a SELECT containing aggregates, both
** non-aggregate field variables and aggregate functions are stored
** in the AggExpr array of the Parser structure.
**
** The pExpr field points to an expression that is part of either the
** field list, the GROUP BY clause, the HAVING clause or the ORDER BY
** clause. The expression will be freed when those clauses are cleaned
** up. Do not try to delete the expression attached to AggExpr.pExpr.
**
** If AggExpr.pExpr==0, that means the expression is "count(*)".
*/
struct AggExpr {
int isAgg; /* if TRUE contains an aggregate function */
};
/*
** An SQL parser context. A copy of this structure is passed through
** the parser and down into all the parser action routine in order to
** carry around information that is global to the entire parse.
*/
struct Parse {
int rc; /* Return code from execution */
char *zErrMsg; /* An error message */
const char *zTail; /* All SQL text past the last semicolon parsed */
** while generating expressions. Normally false */
int nErr; /* Number of errors seen */
int nTab; /* Number of previously allocated VDBE cursors */
int nMem; /* Number of memory cells used so far */
int nSet; /* Number of sets used so far */
int nAgg; /* Number of aggregate expressions */
int nVar; /* Number of '?' variables seen in the SQL so far */
const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
};
/*
** An instance of the following structure can be declared on a stack and used
** to save the Parse.zAuthContext value so that it can be restored later.
*/
struct AuthContext {
const char *zAuthContext; /* Put saved Parse.zAuthContext here */
};
/*
** Bitfield flags for P2 value in OP_PutIntKey and OP_Delete
*/
/*
* Each trigger present in the database schema is stored as an instance of
* struct Trigger.
*
* Pointers to instances of struct Trigger are stored in two ways.
* 1. In the "trigHash" hash table (part of the sqlite* that represents the
* database). This allows Trigger structures to be retrieved by name.
* 2. All triggers associated with a single table form a linked list, using the
* pNext member of struct Trigger. A pointer to the first element of the
* linked list is stored as the "pTrigger" member of the associated
* struct Table.
*
* The "step_list" member points to the first element of a linked list
* containing the SQL statements specified as the trigger program.
*/
struct Trigger {
char *name; /* The name of the trigger */
char *table; /* The table or view to which the trigger applies */
the <column-list> is stored here */
int foreach; /* One of TK_ROW or TK_STATEMENT */
};
/*
* An instance of struct TriggerStep is used to store a single SQL statement
* that is a part of a trigger-program.
*
* Instances of struct TriggerStep are stored in a singly linked list (linked
* using the "pNext" member) referenced by the "step_list" member of the
* associated struct Trigger instance. The first element of the linked list is
* the first step of the trigger-program.
*
* The "op" member indicates whether this is a "DELETE", "INSERT", "UPDATE" or
* "SELECT" statement. The meanings of the other members is determined by the
* value of "op" as follows:
*
* (op == TK_INSERT)
* orconf -> stores the ON CONFLICT algorithm
* pSelect -> If this is an INSERT INTO ... SELECT ... statement, then
* this stores a pointer to the SELECT statement. Otherwise NULL.
* target -> A token holding the name of the table to insert into.
* pExprList -> If this is an INSERT INTO ... VALUES ... statement, then
* this stores values to be inserted. Otherwise NULL.
* pIdList -> If this is an INSERT INTO ... (<column-names>) VALUES ...
* statement, then this stores the column-names to be
* inserted into.
*
* (op == TK_DELETE)
* target -> A token holding the name of the table to delete from.
* pWhere -> The WHERE clause of the DELETE statement if one is specified.
* Otherwise NULL.
*
* (op == TK_UPDATE)
* target -> A token holding the name of the table to update rows of.
* pWhere -> The WHERE clause of the UPDATE statement if one is specified.
* Otherwise NULL.
* pExprList -> A list of the columns to update and the expressions to update
* them to. See sqliteUpdate() documentation of "pChanges"
* argument.
*
*/
struct TriggerStep {
int op; /* One of TK_DELETE, TK_UPDATE, TK_INSERT, TK_SELECT */
int orconf; /* OE_Rollback etc. */
INSERT steps (when pExprList == 0) */
INSERT steps (when pSelect == 0) */
};
/*
* An instance of struct TriggerStack stores information required during code
* generation of a single trigger program. While the trigger program is being
* coded, its associated TriggerStack instance is pointed to by the
* "pTriggerStack" member of the Parse structure.
*
* The pTab member points to the table that triggers are being coded on. The
* newIdx member contains the index of the vdbe cursor that points at the temp
* table that stores the new.* references. If new.* references are not valid
* for the trigger being coded (for example an ON DELETE trigger), then newIdx
* is set to -1. The oldIdx member is analogous to newIdx, for old.* references.
*
* The ON CONFLICT policy to be used for the trigger program steps is stored
* as the orconf member. If this is OE_Default, then the ON CONFLICT clause
* specified for individual triggers steps is used.
*
* struct TriggerStack has a "pNext" member, to allow linked lists to be
* constructed. When coding nested triggers (triggers fired by other triggers)
* each nested trigger stores its parent trigger's TriggerStack as the "pNext"
* pointer. Once the nested trigger has been coded, the pNext value is restored
* to the pTriggerStack member of the Parse stucture and coding of the parent
* trigger continues.
*
* Before a nested trigger is coded, the linked list pointed to by the
* pTriggerStack is scanned to ensure that the trigger is not about to be coded
* recursively. If this condition is detected, the nested trigger is not coded.
*/
struct TriggerStack {
int newIdx; /* Index of vdbe cursor to "new" temp table */
int oldIdx; /* Index of vdbe cursor to "old" temp table */
int orconf; /* Current orconf policy */
int ignoreJump; /* where to jump to for a RAISE(IGNORE) */
};
/*
** The following structure contains information used by the sqliteFix...
** routines as they walk the parse tree to make database references
** explicit.
*/
struct DbFixer {
const char *zDb; /* Make sure all objects are contained in this database */
const char *zType; /* Type of the container - used for error messages */
};
/*
* This global flag is set for performance testing of triggers. When it is set
* SQLite will perform the overhead of building new and old trigger references
* even when no triggers exist
*/
extern int always_code_trigger_setup;
/*
** Internal function prototypes
*/
int sqliteStrICmp(const char *, const char *);
int sqliteStrNICmp(const char *, const char *, int);
int sqliteHashNoCase(const char *, int);
int sqliteIsNumber(const char*);
int sqliteCompare(const char *, const char *);
int sqliteSortCompare(const char *, const char *);
void sqliteRealToSortable(double r, char *);
#ifdef MEMORY_DEBUG
void *sqliteMalloc_(int,int,char*,int);
void sqliteFree_(void*,char*,int);
void *sqliteRealloc_(void*,int,char*,int);
char *sqliteStrDup_(const char*,char*,int);
char *sqliteStrNDup_(const char*, int,char*,int);
void sqliteCheckMemory(void*,int);
#else
void *sqliteMalloc(int);
void *sqliteMallocRaw(int);
void sqliteFree(void*);
void *sqliteRealloc(void*,int);
char *sqliteStrDup(const char*);
char *sqliteStrNDup(const char*, int);
# define sqliteCheckMemory(a,b)
#endif
char *sqliteMPrintf(const char*, ...);
char *sqliteVMPrintf(const char*, va_list);
void sqliteSetString(char **, const char *, ...);
void sqliteSetNString(char **, ...);
void sqliteErrorMsg(Parse*, const char*, ...);
void sqliteDequote(char*);
int sqliteKeywordCode(const char*, int);
int sqliteRunParser(Parse*, const char*, char **);
void sqliteExec(Parse*);
void sqliteExprDelete(Expr*);
void sqliteExprListDelete(ExprList*);
int sqliteInit(sqlite*, char**);
void sqliteResetInternalSchema(sqlite*, int);
void sqliteBeginParse(Parse*,int);
void sqliteRollbackInternalChanges(sqlite*);
void sqliteCommitInternalChanges(sqlite*);
void sqliteOpenMasterTable(Vdbe *v, int);
void sqliteAddNotNull(Parse*, int);
int sqliteCollateType(const char*, int);
void sqliteAddCollateType(Parse*, int);
int sqliteIdListIndex(IdList*,const char*);
void sqliteIdListDelete(IdList*);
void sqliteSrcListDelete(SrcList*);
int,int,int);
void sqliteSelectDelete(Select*);
void sqliteSelectUnbind(Select*);
void sqliteWhereEnd(WhereInfo*);
int sqliteRunVacuum(char**, sqlite*);
int sqliteGlobCompare(const unsigned char*,const unsigned char*);
int sqliteLikeCompare(const unsigned char*,const unsigned char*);
char *sqliteTableNameFromToken(Token*);
int sqliteExprType(Expr*);
int sqliteFuncId(Token*);
void sqliteRandomness(int, void*);
void sqliteRollbackAll(sqlite*);
void sqliteCodeVerifySchema(Parse*, int);
void sqliteBeginTransaction(Parse*, int);
void sqliteCommitTransaction(Parse*);
void sqliteRollbackTransaction(Parse*);
int sqliteExprIsConstant(Expr*);
int sqliteExprIsInteger(Expr*, int*);
int sqliteIsRowid(const char*);
void sqliteBeginWriteOperation(Parse*, int, int);
void sqliteEndWriteOperation(Parse*);
void sqliteRegisterBuiltinFunctions(sqlite*);
int sqliteSafetyOn(sqlite*);
int sqliteSafetyOff(sqlite*);
int sqliteSafetyCheck(sqlite*);
int, int);
void sqliteDeleteTriggerStep(TriggerStep*);
void sqliteDeleteTrigger(Trigger*);
void sqliteDeferForeignKey(Parse*, int);
#ifndef SQLITE_OMIT_AUTHORIZATION
int sqliteAuthCheck(Parse*,int, const char*, const char*, const char*);
void sqliteAuthContextPop(AuthContext*);
#else
# define sqliteAuthRead(a,b,c)
# define sqliteAuthCheck(a,b,c,d,e) SQLITE_OK
# define sqliteAuthContextPush(a,b,c)
# define sqliteAuthContextPop(a) ((void)(a))
#endif
double sqliteAtoF(const char *z, const char **);
char *sqlite_snprintf(int,char*,const char*,...);
int sqliteFitsIn32Bits(const char *);